[c-nsp] IPv6 duplicate address

[Ivan]

So following on from a very old thread 
https://puck.nether.net/pipermail/cisco-nsp/2008-May/051088.html

I have had an event where an interface got stuck in stalled state for 
much longer than is desirable.  I tried to fix it using "ipv6 nd dad 
attempts 5" but no luck.  I also tried disabling and enabling IPv6 on 
the interface that also didn't work.  Manually setting the link-local 
address (and setting back) fixed things, but I have a few questions.

Does DAD just stay in stalled state until some kind of manual 
intervention takes place?  (Perhaps there is a method of have periodic 
retires?)

Does "ipv6 nd dad attempts 5" help?  How often are attempts made by 
default.  I am thinking this could help prevent the stalled state in the 
future.

This for IOS 15.2(4)S1 on an ASR1k.

Thanks

Ivan